How to Keep Gerbils from Declanning: Tips and Tricks for a Happy Colony?

Declanning is a behavior where gerbils that were previously living together peacefully start to show aggression towards each other, leading to fights and social isolation. This can happen for various reasons, such as overcrowding, improper socialization, or even a change in the gerbils’ environment. Gerbils are territorial animals and may become aggressive when they feel their space is being invaded. Understanding gerbil behavior and social structure is the first step in preventing declanning.

Understanding Gerbil Behavior

Social structure of gerbils

In the wild, gerbils live in large family groups, with a dominant male and female pair leading the colony. The other gerbils in the group are subordinate to the alpha pair and follow a strict social hierarchy. In captivity, gerbils will often form similar social structures, with one dominant pair leading the group. Understanding this social structure is important when introducing new gerbils to an existing colony.

Communication and body language

Gerbils communicate with each other through various means, including vocalizations, scent marking, and body language. Understanding their communication cues can help you identify and prevent declanning. For example, when gerbils are feeling threatened or aggressive, they may thump their hind legs, make a hissing sound, or puff up their fur. Similarly, when gerbils are friendly and relaxed, they may groom each other or curl up together for a nap.

Identifying Signs of Declanning

Aggression and fighting

The most obvious sign of declanning is when gerbils start to fight with each other. This can include chasing, biting, and wrestling. Gerbils that were previously friends may suddenly become aggressive towards each other, and this can escalate quickly if not addressed.

Social isolation and avoidance

Gerbils that are declanning may start to avoid each other, spending more time in separate areas of the cage. They may also become territorial over certain areas or toys in the cage.

Changes in activity level and appetite

Declanning can be stressful for gerbils, and this can manifest in changes in their activity level and appetite. Gerbils may become less active or spend more time hiding in their nests. They may also lose interest in food or become less social with their owners.

Preventing Declanning

Proper cage size and layout

One of the most important factors in preventing declanning is providing a proper cage size and layout for your gerbils. Gerbils need plenty of space to run, play, and establish territories. A general rule of thumb is to provide at least 10 gallons of space per gerbil. Additionally, providing plenty of hides, tunnels, and toys can help prevent territorial disputes.

Adding new gerbils to the colony

When adding new gerbils to an existing colony, it’s important to do so slowly and carefully. Introducing new gerbils too quickly can lead to fighting and declanning. One common method is to use a split cage, where the gerbils are kept separate but can still interact through a wire mesh barrier. This allows them to get used to each other’s scent and presence before being fully introduced.

Using scent swapping and split cage methods

Another method for introducing new gerbils is scent swapping. This involves rubbing the new gerbils with a cloth or bedding from the existing colony, and vice versa. This allows the gerbils to get used to each other’s scent before being introduced. Additionally, using a split cage method can help prevent fighting and declanning.

Resolving Declanning

Separating gerbils and reintroducing them

If declanning does occur, it’s important to separate the gerbils before any serious harm is done. Once the gerbils have been separated, you can try reintroducing them slowly, using the same methods as when introducing new gerbils. This may take time and patience, but it’s important to ensure the safety and well-being of your gerbils.

Introducing neutral territory

Another method for resolving declanning is to introduce neutral territory. This can be a separate play area or a completely new cage. By introducing a new environment, it can help reset the gerbils’ social structure and prevent further fighting.

Seeking veterinary advice

If declanning persists or results in injuries, it’s important to seek veterinary advice. Your vet can provide guidance on how to treat any injuries and may be able to recommend additional methods for resolving declanning.

Maintaining a Happy Colony

Proper nutrition and hydration

Ensuring your gerbils have proper nutrition and hydration is key to maintaining a happy colony. Gerbils should have access to fresh water and a balanced diet of pellets, fresh vegetables, and occasional treats.

Providing mental and physical stimulation

In addition to a proper diet, gerbils need mental and physical stimulation to prevent boredom and promote overall well-being. Providing plenty of toys, tunnels, and hides can help prevent declanning by providing different areas for gerbils to explore and establish territories.

Regular cleaning and maintenance

Regular cleaning and maintenance of your gerbils’ cage is important to prevent the spread of illness and promote overall hygiene. This includes cleaning out soiled bedding and toys, as well as providing fresh water and food daily.


Keeping a happy gerbil colony requires understanding their behavior, identifying signs of declanning, and taking steps to prevent and resolve any issues. By providing a proper cage size and layout, introducing new gerbils slowly, and providing mental and physical stimulation, you can help prevent declanning and maintain a happy and healthy gerbil colony. If declanning does occur, it’s important to act quickly to separate the gerbils and reintroduce them slowly. With time and patience, you can help your gerbils live together in harmony.

ThePetFaq Team